全文获取类型
收费全文 | 659篇 |
免费 | 43篇 |
专业分类
林业 | 22篇 |
农学 | 27篇 |
基础科学 | 3篇 |
54篇 | |
综合类 | 68篇 |
农作物 | 25篇 |
水产渔业 | 59篇 |
畜牧兽医 | 410篇 |
园艺 | 12篇 |
植物保护 | 22篇 |
出版年
2021年 | 10篇 |
2020年 | 9篇 |
2019年 | 14篇 |
2018年 | 8篇 |
2017年 | 17篇 |
2016年 | 10篇 |
2015年 | 13篇 |
2014年 | 13篇 |
2013年 | 33篇 |
2012年 | 22篇 |
2011年 | 25篇 |
2010年 | 21篇 |
2009年 | 15篇 |
2008年 | 21篇 |
2007年 | 18篇 |
2006年 | 29篇 |
2005年 | 37篇 |
2004年 | 21篇 |
2003年 | 24篇 |
2002年 | 33篇 |
2001年 | 21篇 |
2000年 | 17篇 |
1999年 | 16篇 |
1998年 | 6篇 |
1997年 | 7篇 |
1996年 | 4篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 9篇 |
1991年 | 13篇 |
1990年 | 6篇 |
1989年 | 9篇 |
1988年 | 7篇 |
1987年 | 19篇 |
1986年 | 10篇 |
1985年 | 11篇 |
1984年 | 7篇 |
1983年 | 6篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 14篇 |
1978年 | 10篇 |
1977年 | 4篇 |
1975年 | 6篇 |
1974年 | 6篇 |
1973年 | 7篇 |
1972年 | 7篇 |
1970年 | 8篇 |
1969年 | 8篇 |
1967年 | 4篇 |
排序方式: 共有702条查询结果,搜索用时 279 毫秒
131.
132.
Association analysis reveals effects of wheat glutenin alleles and rye translocations on dough-mixing properties 总被引:2,自引:0,他引:2
Shusong Zheng Patrick F. Byrne Guihua Bai Xueyan Shan Scott D. Reid Scott D. Haley Bradford W. Seabourn 《Journal of Cereal Science》2009,50(2):283-290
The glutenin loci of wheat (Triticum aestivum L.) are important determinants of bread-making quality, although the effects of alleles at those loci are incompletely understood. We applied an association analysis method to assess the effects of glutenin alleles and 1RS wheat–rye (Secale cereale L.) translocations on dough-mixing properties in 96 wheat cultivars and advanced lines grown at three Colorado locations while accounting for population structure and relatedness of individuals in the population. The results indicated that (1) in the majority of cases, controlling relatedness of individuals reduced the significance of associations between glutenin loci and Mixograph traits; (2) the Glu-D1 and Glu-B3 loci and 1RS translocations had greater impacts on dough-mixing properties compared to other glutenin loci; (3) Glu-B1w, Glu-D1d, and Glu-B3b were consistently associated with greater (more favorable) Mixograph peak time (MPT) than other alleles at the respective loci, whereas Glu-B1e, Glu-D1a, and Glu-B3c were associated with reduced MPT; (4) the 1BL.1RS translocation was associated with a decrease in Mixograph properties. Our results indicate that taking multiple-level relatedness of individuals into account can improve the results of association analysis for wheat-quality traits. 相似文献
133.
Five methods that employed very different testing principles and procedures for assessing gluten quality were compared for 33 North American soft red and white wheats. The three methods analyzed flour (alveograph work, lactic acid solvent retention capacity, and mixograph peak time) and two methods employed ground wheat meal (Glutomatic gluten index and SDS sedimentation volume). Compared against the normalized mean of all five assessments, the ability of the assessment methods to evaluate gluten quality decreased in the order: alveograph work, lactic acid solvent retention capacity, mixograph peak time, Glutomatic gluten index, and SDS sedimentation volume. The methods utilizing flour were substantially superior predictive methods; however, the two meal‐based methods could be sufficient for early generation screening when flour is not available. 相似文献
134.
The new systems of protein evaluation distinguish clearly between the requirement of the rumen microbes and the need of the host animal. While the requirement of the rumen microbes and the production of microbial protein is related to fermented energy, the need of the host animal varies with type and level of productivity. In dairy cows microbial protein is insufficient for the host animal, particularly when the animals are in negative energy balance, and in order to efficiently utilise body energy reserves undegraded protein must be given. Several experiments are discussed in which dairy cows have been given ammonia treated straw as the only source of roughage and where milk yields have been maintained. It is emphasised that increased use of high roughage diets in early lactation increases the demand for undegraded proteins. The converse is also true: that undegraded protein increases the proportion of roughage that can be used for high yielding dairy cows. 相似文献
135.
136.
The effect of manipulating adult turkey cecal contents was assessed. Treatment of day-old poults with cecal contents diluted up to 1/3000 protected 90% of the birds against subsequent challenge with 10(3) colony-forming units of Salmonella typhimurium. The addition of penicillin G and streptomycin to adult cecal contents reduced their protective effects by 20% and 50%, respectively. When cecal contents were heat-treated at 65 C for 15 minutes or filter-sterilized, the protective properties were lost. Anaerobic cultures of cecal contents in reinforced clostridial medium afforded protection against challenge, but protection was lost on subsequent subcultures. Thioglycollate broth culture of cecal contents did not protect. 相似文献
137.
138.
139.
The pharmacokinetics of propofol were investigated in two groups of five Scottish blackface sheep undergoing surgery for the implantation of subcutaneous tissue pouches. After premedication with acepromazine and papaveretum, anaesthesia was induced with either propofol at 4 mg kg−1 intravenously (group 1) or with a mixture of propofol at 3 mg kg−1 and ketamine at 1 mg kg −1 intravenously (group 2). Anaesthesia was maintained with a variable infusion rate of either propofol alone (group 1) or propofol and ketamine (group 2). Both regimens produced satisfactory conditions for superficial surgery of the body surface. The mean (SD) duration of anaesthesia was 64·8 (3·1) minutes for group 1 and 60 (0) minutes for group 2; the mean total dose of propofol given to the sheep in group 1 was 801 (84) mg, and the sheep in group 2 received 470 (46) mg of propofol and 267 (30) mg of ketamine. The mean elimination half-life of propofol was 56·6 (13·1) minutes in group 1 and 50·3 (21·4) minutes in group 2; the mean volume of distribution at steady state was 1037 (0480) litre kg−1 in group 1 and 1·515 (0939) litre kg−1 in group 2; the mean body clearance was 85·4 (28·0) ml kg−1 min−1 in group 1 and 1280 (35·0) ml kg−1 min−1 in group 2; the mean residence time corrected for a bolus injection was 12·1 (4·2) minutes in group 1 and 11·9 (6·6) minutes in group 2; for the infusion, the mean residence time was 72·1 (4·2) minutes in group 1 and 69·9 (7·9) minutes in group 2. There were wide variations in the blood propofol concentrations reached in individual sheep by using this standard dosing regimen. All the sheep recovered quickly from anaesthesia; the mean times to extubation, sternal recumbency and standing for the animals in group 1 were 2·8 (0·4) 6·3 (1·2) and 10·9 (1·6) minutes from the end of the infusion, and the times for group 2 were 5·3 (0·9), 11·2 (1·7) and 15·1 (2·2) minutes. 相似文献
140.
J L Wessale L A Smith M Reid W Janas A B Carter L A Geddes 《American journal of veterinary research》1985,46(10):2129-2132
The auscultatory method was used to obtain indirect systolic and diastolic pressures in 13 dogs anesthetized with either halothane or sodium pentobarbital (30 mg/kg of body weight). Korotkoff sounds were obtained, using a 1-cm (diameter) piezoelectric element cemented to the inner surface of a pediatric cuff (width 5.5 cm) which was placed on a shaved thoracic limb (membrum thoracicum). The signal from the piezoelement was amplified by a differential amplifier (30 to 200 Hz) and a commercially available audio amplifier. Indirect pressure (I) was compared with direct pressure (D) in the brachial, femoral, or carotid artery. The linear regression lines and correlation coefficients (r) for the data were as follows: systolic, I = 0.94 (D) + 1.1, r = 0.98; diastolic, I = 0.99 (D) + 3.2, r = 0.99. The quality of the Korotkoff sounds and the accuracy of the determinations were best in the halothane-anesthetized dogs. These results indicate that indirect auscultatory systolic and diastolic pressures are in excellent agreement with the directly measured pressures. 相似文献